<!DOCTYPE html>
<html>
<head>
<style>
.button {
 /* background-color: #4CAF50;  绿色 */
  border: none;
  /* color: white; */
  padding: 15px 32px;
  text-align: center;
  text-decoration: none;
  display: inline-block;
  font-size: 16px;
  margin: 4px 2px;
  cursor: pointer;
  background-color: white; 
  color: black; 
}

.button1 {

  border: 2px solid #4CAF50;
}

.button2 {
  border: 2px solid #008CBA;
}

.button3 {
  border: 2px solid #f44336;
}

.button4 {
  border: 2px solid #e7e7e7;
}

.button5 {
  border: 2px solid #555555;
}
</style>
</head>
<body>

<h1>有颜色的按钮边框</h1>

<p>请使用 border 属性为按钮添加边框：</p>

<button class="button button1">绿色</button>
<button class="button button2">蓝色</button>
<button class="button button3">黑色</button>
<button class="button button4">灰色</button>
<button class="button button5">黑色</button>

</body>
</html>
